# import numpy as np

# a = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])

# print(a.shape)

# zero_array = np.zeros(3)
# print(zero_array)

# zero_array_2d = np.zeros((3, 4))   # 3行4列
# print(zero_array_2d)

from pandas import Series

lst = ['python', 'c++', 'c#', 'java']
# print(Series(lst))
ser = Series(lst, index=['a', 'b', 'c', 'd'])
# print(ser)


score_dict = {
    'python': 100,
    'c++': 99,
    'c#': 98,
    'java': 97
}
ser = Series(score_dict)
print(ser)

ls = ['1', '2', '3']
print(ls[::-1])